Electrical lighting has become commonplace in modern society. Electrical lighting devices are commonly deployed, for example, in homes and buildings of commercial and other enterprise establishments. Traditional general lighting devices have tended to be relatively dumb, in that they can be turned ON and OFF, and in some cases may be dimmed, usually in response to user activation of a relatively simple input device. Such lighting devices have also been controlled in response to ambient light detectors that turn on a light only when ambient light is at or below a threshold (e.g. as the sun goes down) and in response to occupancy sensors (e.g. to turn on light when a room is occupied and to turn the light off when the room is no longer occupied for some period). Often such devices are controlled individually or as relatively small groups at separate locations.
With the advent of modern electronics has come advancement both in the types of light sources and in the control capabilities of the lighting devices. For example, solid state sources are now becoming a commercially viable alternative to traditional light sources such as incandescent and fluorescent lamps. By nature, solid state light sources such as light emitting diodes (LEDs) and organic LEDs (OLEDs) are easily controlled by electronic logic circuits or processors. For example, many fixtures or systems using solid state light sources enable control of both intensity and color characteristics of the overall light output. Electronic controls have also been developed for other types of light sources.
Traditional control algorithms involved setting a condition or parameter of the light output, such as intensity and/or color and then maintaining the set condition within some minimal variance for a relatively long period of time, e.g. over a work day or a period occupancy. Advanced electronics in the control elements, however, have facilitated more sophisticated control algorithms. For example, some systems have been configured to vary a condition of lighting in accordance with a circadian rhythm. A circadian rhythm is a biological function that corresponds to a natural 24 hour cycle. For lighting purposes, lighting in an office or the like has been controlled in a manner to simulate variations of natural daylight over some portion of the daytime during which the office is expected to be occupied, so as to simulate that portion of the natural 24 hour cycle of sunlight.
Control algorithms based in whole or in part on a circadian rhythm may help to promote harmony of the occupants with the lighted environment. However, such algorithms are still somewhat limited in that they tend to follow a general trend, such as average intensity of daylight, over the relevant period of the day.
The Fraunhofer Institute developed a Virtual Sky® in the form of a ceiling grid that was illuminated to appear as a moving sky with variable light intensity and sky colors. However, this approach is essentially an emulation of a natural environmental condition not specifically configured to manipulate the environment to influence an occupant's sense of being. Also, such a lighting grid is far too complex and expensive for wide adoption in environments for typical spaces intended for human occupancy, such as homes, offices, agricultural buildings, commercial buildings or the like.
Other types of lighting have been controlled in response to various conditions or inputs, for example, in response to music. At least some musical sound may be considered chaotic. However, lighting in response to or coordinated with music has been intended for special effects lighting or entertainment and not for control of general lighting such as task lighting in an enterprise or residential space.
Hence, there is room for still further improvement in a lighting control algorithm to better promote an objective purpose of an illuminated area or space when occupied, and/or which can be implemented using devices or systems for general lighting that are readily adaptable to environments for typical spaces, such as homes, offices, agricultural buildings, commercial buildings or the like.